Apparatus and method for forming apertures in molded pulp articles



Feb. 2, 1960 A. E; coMsTocK 2,923,654

APPARATUS AND METHOD FOR FORMING APERTURES IN MOLDED PULP ARTICLES 4Sheets-Sheet 1 Filed Jan. 6, 1955 IN VEN TOR. dZf/ed E Como/z, BY

Feb. 2, 1960 A. E. COMSTOCK APPARATUS AND METHOD FOR FORMING APERTURESIN MOLDED PULP ARTICLES Filed Jan. 6, 1955 4 Sheets-Sheet 2 A. E.COMSTOCK 2,923,654 APPARATUS AND METHOD FOR FORMING APERTURES IN MOLDEDPULP ARTICLES Filed Jan. 6, 1955 Feb. 2, 1960 4 SheetS -Sheet 3 Feb. 2,1960 v A. E. coMsTocK 2,923,654

APPARATUS AND METHOD FOR FORMING APERTURES IN MOLDED PULP ARTICLES FiledJan. s, 1955 4 Sheets-Sheet 4 ul l lfl HFH H I I. HHWHHJ III. I.

4 INVENTOR. dlfredlTConwtoa/e,

United States Patent APPARATUS AND METHOD FOR FORMING APERTURES INMOLDED PULP ARTICLES Alfred E. Comstock, Palmer, Mass., assignor, bymesue assignments, to Diamond National Corporation, a corporation ofDelaware Application January 6, 1955, Serial No. 480,193 14 Claims. (Cl.162-228) The present invention relates to improvements in a continuouslyacting apparatus by which special molded pulp cartons and like objectsare formed. In accordance with the known practice, this is done by thedeposition on a shaped, mesh-like or foraminated screen of a feltedlayer of wet pulp fibers, which are drawn onto the surface of the screenby suction applied to the opposite side thereof. Continuous rotaryapparatus of this general type is commonly employed in the manufactureof molded pulp egg cartons, an example of which is shown in the patentto J. W. Cox No. 2,529,140 of November 7, 1950.

The present improvement deals with apparatus capable of formingapertures in a surface of one of the component sections of such a cartonas an incident of the molding operation, and as such deals particularlywith equipment for the formation of a lock type carton which is arefinement of the molded carton of the Cox patent. An example ofapertures in asurface of a component section of a carton is illustratedin the patent to Koppelman No. 2,093,280, of September 14, 1937.

While the Cox and Koppelman cartons differ materially in theirfunctional attributes, it may be assumed that the improvement of theinvention has applicability in common to the molding of all thereof. Inthis, the formation of an improved locking aperture or apertures in amolded pulp article, involving an air jetting operation during theactual wet molding procedure, is the common objective. This aperturingconstitutes a part of the locking provisions of a carton by which itscover and bottom sections are releasably lockedtogether.

It is an important feature of the improved appartus that it operatesduring the molding cycle in such fashion as not to slow down the outputcapacity of a conventional molding machine in any degree. Nor does itdetract in any way from the quality of the molded article, as a whole,while vastly improving the character of the desired aperture, in respectto the clcanness of definition of its margins, over what has heretoforebeen attainable by any molding equipment or procedure. This isaccomplished in spite of the inherent tendency of the wet fibers todeposit and build up about the periphery of an imperforate plug commonlyused in the molding of apertures, or onto any imperforate surfaceincorporated in a molding or forming die, with a resultant rough,feathered or deckle edge effect in the completed article. Since edgesurfaces of this character are inconsistent with the intended lockingaction of the Reifers type carton, as hereinafter fully described byreference to the drawings, the elimination thereof is an essentialobject of the present improvement.

The basic molding apparatus, as generally shown herein, is acontinuously acting rotary pulp molding machine. Molding forms or dies,characterized by a stably supported, mesh-like or forarninate screensurface shaped in the outline of the desired article, are mounted onappropriate die holders, which are in turn mounted in aligned sets onmolding heads or boxes carried by radially extending arms or likesupports of the machine. So

mounted, the forms are caused to travel in immersed relation to a-supplyof a watery slurry of pulp fibers contained in a stationary tank.

emerging from the slurry a phase ensues in which an'air pressure jettingis performed on the wet layer adjacent the areas of the rough aperturesresulting from nondeposition of fibers, and it is with this operationalphase that the invention deals. The wet molded and properly aperturedarticles are then transferred by suction,"positi ve air pressure, or a'combination of these, onto drying forms,

by which they are carried through a drying oven and thoroughly dried.

Air jetting as mentioned above comes into play at the instant the faceof the molding screen at the aperture area comes clear of the slurry,for if the action is retarded it does not fully avoid a deckle effect atthe aperture edge in question, while if premature, an undue thinning ofthe pulp material around the aperture results. As the jetting is bestperformed, a sharp definition of the aperture is obtained due to theapplication of an air jet stream in a carefully determined annularpattern, and one or the other of the disturbing phenomena will arise ifthe timing is not correct.

Specifically considered, and as distinguished from prior practice inwhich molded apertures are produced by the simple plugging, or otherwiserendering impermeable to fluid, of a predetermined area of a moldingscreen, hence screen in an aperture thereof which corresponds with thecross sectional outline of the shell. The shell is appropriately securedin place in this relation both to the form or die and to a rigid dieholder, which mounts the die and constitutes an individual suction boxfor the same as in prior practice. The interior of the shell iscommunicated, at its outer, rear or die holder end, with an air pressuremanifold. I

A specially shaped jet core is fixedly, though removably, held byfriction in the interior of the jet shell, being spaced a trifle fromthe latter at its sides to afford re stricted orifices of specialdesign. Through these orifices air jets are properly directed toshapethe margin of the aperture left at the face of the core in thedesired cleancut fashion. The improved core is of a hounds tooth design,having spaced rearwardly extending prongs adapting the same for tightfrictional engagement with the interior of the shell, so as to maintainit in place without likelihood of being dislodged in normal operation.The prongs additionally serve in conjunction with the main body portionof the core, and in conjunction with the jet shell, in controlling thefiow of the air jet to and through the orifices. The core is removablefor inspection, cleaning or replacement, if desired.

The rear of the improved jet assembly, as thus gener-' Patented Feb. 2,1960 extending, elongated pressure header servicing all the die holderson the platen, the header being rig'dly applied to the rear of theplaten and being communicated with the respective manifolds throughappropriate apertures in the platen; These are, of course, in additionto and quite separate from its conventional suction openings referred toabove.- Each of the platens on the respective rotary molding heads ofthe apparatus thus services a plurality of die'h'olders and forming diesas the same emerge from the pulp slurry.

Since the forming heads are, in accordance with the apparatus oftheabove identified Cox application, swiveled on radially extendingsupports, this swiveled mounting entails the use of a rotatable type ofjoint for an air pressure line supplying the longitudinal pressureheaders; and since the rotary structure as a whole is pressure suppliedfrom a stationary source, the individual air pressure lines to therespective rotating heads are each connected in sealed relation to arotary distributor disk on the main axis of the machine. This disk hasaxially sealed, sliding engagement with an arcuate distributor valvewhich is received in anannular" groove in a face of the distributordisk, being spring urged against the latter to avoid pressure loss atthe sliding joint. Air is applied to this distributor valve from apressure line controlled by an intermittently acting, cam-controlled,automatic valve, which operates to initiate and terminate an air jettingphase in properly timed relation to the molding phase.

Through the agency ofpressure jetting and timing instrumentalities ofthe general character referred to, each of the molding heads issubjected to air jetting exactly at the conclusion of fiber deposition,and no diminution of speedof operation of the machine is required.Moreover, the provisions are such that the timing of jetting cycles isaccurate and foolproof for each of the several individual suctionmolding heads. Considering the extremely flimsy character of the wet,relatively thin layer of pulp fibers on which the hole-defining jettingoperation; is carried out, it will be appreciated that a probelrn of themost serious sort is presented in regard to the preservation of thefibers directly adjacent the desired opening in a properly distributedlayer of unform depth, yet with a sharply cut off margin at the opening,as distinguished from a rough or deckle edge. Both the automatic timingprovisions and specific structural features of the individual jetassembl es are notable for their success in meeting this problem,particularly at the relatively high speed at which the apparatusperforms the operations referred to above.

The foregoing statements are indicative in a general Way of the natureof the invention. Other and more specific objects will be apparent tothose skilled in the art, upon a full understanding of the constructionand operation of the improvement.

A single embodiment of the invention is presented herein for purpose ofillustration. It will be appreciated that the invention may beincorporated in other modified forms coming equally within the scope ofthe appended claims.

In the drawings:

Fig. 1' is a fragmentary view partially in end elevation which is moreor less schematic in character, insofar as the molding machine structureas a whole is concerned, a portion of the view being shown in transversevertical section through a molding head of the machine to show theimproved features of the invention in a general way;

Fig. 2 is a view in irregular or discontinuous section along't'hegeneral line of the jet air pressure supply to a molding unit of theapparatus, i.e., approximately along line 2 2 of Fig. 1, the View beingotherwise broken away and sectioned to illustrate further specificdetails;

Fig. 3 is a top plan view of a molded pulp carton formed by theapparatus, the carton being shown open and upwardly exposed to view;

Fig 4'' is a fragmentary plan View, partially broken away, illustratinga portion of a platen, die holder and die unit of the apparatus, inwhich one aspect of the improvement is presented, showing the same inrelation to a pressure distribution header of the jet supply line;

Fig. 5 is an enlarged fragmentary view in transverse vertical sectionalong a line corresponding to line 55 of Pig. 4, generally illustratingfeatures of an improved jet assembly;

Figs. 6 and 7 are, respectively, enlarged fragmentary views in crosssection along lines 6-6 and 7-7 of Fig. 5, further showing therelationship o-fcomponnt parts of the jet assembly;

Figs. 8A and 8B are, respectively, views in side elevation of the jetcore and jet shell of the assembly in question;

Pig. 9 is a rear plan View of a die-box platen and pressure distributionheader assembly otherwise depicted in Fig. 4, this view beingapproximately from line 9--9 of Figs'l and 2;

Fig. 10 is a fragmentary sectional View, approximately along line lit-1dof Figs. 4 and 9, further illustrating the construction of thedistributor header referred to, as well as its relation to the platenand die holders of the molding head, the holders being indicated indot-dash Pig. ll is a fragmentary view in horizontal section along linei l-l1 of Fig. 1, illustrating details of a pressure distribuitonsliding valve subassembly of the apparatus;

Fig, 12 is a fragmentary side 'elevational view of amaster air pressurevalve control unit of the apparatus and the provisions for mounting thesame; and

Fig. 13 is a view in transverse vertical section along line iii-13 ofFig. 12.

Reference should first be made to Figs. 1 and 2 for a general showing ofthe structural features of the improvement as they are related. tosuction pulp molding equipment such as is illustrated and described in acopending application of John V]. Cox, Serial No. 266,729, identifledabove. In this connection, reference may also be had to Fig. 3 of thepresent drawings for an illustration of the type of molded pulp carton,further shown and described in the above identified Reifers application,which the present improvements are instrumental in form ng.

The reference numeral 10 generally designates a heavy cast or weldedframework of the apparatus, this framework and associated parts havingappropriate provisions, of no bearing on the present invention, for thecommunication of a vacuum with suction boxes of the several individualmolding heads of the apparatus. These are generally designated 11.Framework 10 provides a bearing for a longitudinally extending maindrive shaft 12 of the apparatus, and a large fixed control cam l3,governing compound movements of the heads 11 in operation, is suitablysupported on the frame. The cam is shown only to the extent of itsgeneral over-all outline, since its details and function in regard tocontrolling the movements of heads 11 may all 'be as illustrated in theCox application and, as such, form no part of he present invention. Itmay be assumed that these heads are appropriately supported, as by therotary spider means of that application, and that they are controlled bysuitable cam followers engaging cam 13, also in the fashion shown insaid application.

Main drive shaft 12 has fixedly mounted thereon a pressure distributordisk- 14 of relatively large diameter, the outer periphery of the diskbeing thickened at 15 and provided with an axially extending peripheralflange l6; and an annular internal ring 17 coacts with flange la indefining an axially opening annular groove 18 facing outwardly of thedisk. A hollow tubular hub 19 is keyed to rotate with shaft 12, and thishub carries a plurality of radiating chambered housings 20 on whichvacuum heads 11 are swiveled, through which vacuum is communicated withthe interior of each head during" the molding cycle.' Reverse positivepressure (other than hole jetting pressure) mayjalso be transmittedthrough these spaces during a transferphase in which the molded articleis shifted onto a drying form. Since the special provisions in regard tosuction passage means and to the mounting of the molding heads do notconstitute part of the invention, a brief and generalized descriptionthereof will sufiice.

Each head comprises a suction box 22 bolted to a housing and defining inpart an internal suction chamber 23, a hollow, radially extending neck24 of the box communicating the housing with the suction chamber. Aswiveled die support 25 is provided with journals 26 at opposite endsthereof which are mounted by antifriction sleeve bearings on theopposite ends of a swivel shaft 27. Shaft 27 is suitably borne by theouter end of suction box 22, the pivoting provisions includingappropriate pressure seals at the axial meeting surfaces of therelatively moving parts, thus enabling a limited rotative movement ofthe support 25, and associated parts to be described, in reference tothe radially'extending spider and passageway provisions. the means tosupply air under pressure to the pivotally mounted members that theimprovements of the present invention deal, in one of its aspects, andsuch means will now be described.

Referring again to the pressure distribution disk 14 shown in Figs. 1and 2, and also in Fig. 11, it is provided with a plurality of ports 30spaced uniformly thereabout, one for each head 11, and extendingtherethrough to communicate with the annular groove 18 of the disk.These ports are each tapped for the reception, from the inner side ofthe disk, of an individual pressure supply line of flexible characterfor each of the molding heads 11.

This line comprises an L 31 secured in port 30, a nipple 32 leading to abranch T 33, from which a branch pipe 34, as connected by a union 35with a similar pipe 36 and a coupling 37, extends longitudinally throughthe entire axial length of the molding head in question. Furtherassemblies of pressure supply and distribution elements are in turnassociated with the T 33 and coupling 37, and they are identical thoughoppositely arranged; accordingly only one of these assemblies will bedescribed, on the understanding that corresponding parts andrelationships of the other are designated by corresponding referencenumerals, primed, and have corresponding functions.

A ninety degree street L 38 is associated with T 33 and is placed incommunication, by a line including a union 39, with a rotatable joint 40of well known construction. This joint permits swiveling action of thepressure supply line at suction box 22, being piloted on the outer axialend of molding'head swivel shaft 27. The piloting provisions (Fig. 2)take the form ofa sleeve bushing 42 set in the end of shaft 27, in whicha threaded stud 43 is received as a pilot to mount the joint 49 in thebushing, the stud being threadedly received by the shaft end. p

A connector pipe and L 44 communicate the fluid pressure line as so fardescribed with an end of an elongated pressure distributor header 45which is formed with a continuous conduit groove 46 along practicallyits entire length. Groove 46 opens to the outer surface of head 45 toface the rear surface of a relatively large, die-supporting platen 47(see Figs. 1, 2, 4, 9 and 10), which: platen extends across the entireaxial length of each molding head 11. It affords a mount for a group ofindividual, box-like die holders 48, along with the respective formingdies 49 and associated jetting provisions with which another aspect ofthe invention deals, as will be hereinafter described in greater detail.

Swiveled pressure piping provisions of the above character insure thatas pressure distributor disk 14 rotates in the normal operation of themolding apparatus, air

It is with illustrated in Fig. 1, being provided with apertures toappropriate support, such as a frame I-beam 71.

head 63.

under a pressure of, say, two pounds per square inch, supplied at a rateof about twenty-four cubic feet per minute, will be successivelyintroduced into the respective lines of piping to the swiveled heads,and to the respective pressure distribution headers 45 by which it iscarried across each platen 47 and admitted there-' through to theinterior of the respective die holders 48, to be applied to the formingdies 49 thereof (shown in Figs. 4 and 5), in a fashion to be laterdescribed.

Air is supplied to the distributor disk 14 by the stationary valvingprovisions illustrated in Figs. 1, 2 and 11. As appears in thesefigures, a ported valve segment 56 of arcuate outline (Fig. l) is fittedconcentrically in groove 18 of disk 14, the valve 50 being provided withan arcuate valve chamber 51 in a fiat side thereof which faces the disk.intermediate its length, valve .50 is provided with an outwardlyextending boss 52 (Figs. 1 and 2) which is drilled to provide a passageopening to chamber 51. Anair pressure supply tube or pipe 54 is.

tapped into the outer end of this passage.

Valve 50 is resiliently urged against distributor disk 14 by a pair ofcoil springs 55 (Figs. 2 and 11). These surround outwardly extendingbosses 56 on the valve which are arranged in arcuately spaced relationto one another on opposite sides of passage boss 52. As shown in Fig.11, each boss 56 is bored and tapped to receive the threaded end of apilot stud 58 of substantial length, and each stud is guided axially ina bushing 59 which is flanged at 60 to rearwardly abut against one endof a special mounting bracket 62. H

Bracket 62 is of generally arcuate configuration, as

receive the pilot studs 58, which are provided with slotted outer screwheads 63 on the opposite side of the bracket. Springs 55 act between therear of valve 50 and pilot bushing flange 6t) tourge the valve into thegroove 18 of pressure distribution disk 14 with uniform force, which maybe adjusted as desired by manipulation of stud As illustrated in Figs. 1and 11, bracket 62 is provided with an integral attaching plate 64, asto which it as braced by a triangular web 65, the attaching plate beingbolted to a suitable side surface of the framework 10. Plate 64 carriesan outwardly extending flanged wing 66 which is bolted to the undersideof an integral boss 67 on frame 10.

If desired, valve 50 may also be provided with an appropriate oilfitting 67 of conventional design, which communicates through suitableinternal porting with the distributor disk groove 18, thereby affordingthe lubrication necessary to keep the working surfaces of the valve 50and disk in efiicient condition.

The supply or air under pressure to valve 50 through pipe or conduit 54is preferably further controlled by a master timing valve unit,illustrated only in Figs. 12 and 13 and generally designated by thereference numeral 68. The valve 68 comprises a hollow valve body 69mounted on a special bracket 70 which is bolted on an Bracket 70includes a horizontal platform element 72 of inverted chanel-shapedcross section, to which the body 69 of the valve 68 is secured independing relation. Platform 73 accommodates the piping or tubing whichconnects valve 68 with a source of pressure supply on the one hand andwith the pipe or conduit 54 on the other hand.

A control plunger 74 extends downwardly of valve body 69 and is actuatedby a cam follower roller 75 which is appropriately mounted for slidingmovement in reference to the valve body 69. Roller 75 engages theperiphery of a generally circular cam 76 secured on a shaft. 77, whichmay be driven by a bevel gear connection to the main shaft 12 of theapparatus. Cam 76 is shaped to provide diametrically opposed lows 78which, when engaged by follower 75, cause valve 68 to be opened, thuscommunicating conduit 54 with the source 7 ofiair pressure, as throughpiping 79 is thevalve. At other times, valve 68 is closed.

Opening of master valve es takes place as the forming. dies 49 mountedin each of die holders 48 emerge from; the pulp slurry, from which alayer of fibers has just been suction deposited. letting of the formingdies then takes place, for a time determined by the arcuate extent ofcam low 73, and by the duration of sliding communication of distributorvalve 5ft with a port 30 of distributor disk 14. At this timecommunication is completed through the line of swiveled piping to anindividual distributor header 415, thence through a platen 47 to theinterior of the die holders 48 associated with it.

through supplement Figs. 1 and 2 in reference to the construction andfunction of the individual forming dies 39, the mode of mounting thesame in a longitudinally extending group on a platen 47 ofconsiderablearea, and the relationship to the die and die holder (if theindividual jet units or assemblies, generally designated 8% by which anair stream is applied to sharply' define the margin of an apertureotherwise formedin that surface by the jet unit. Prior to consideringthese matters it is well to give consideration to the nature of theactual molded pulp carton C (Fig. 3) which the present apparatus isadapted to form. This, as indicated above, is the subject matter of acopending Reifefs appliation but it is also similar, in generalreference to its aperturing, to Cox and Koppelman cartons identifiedabove.

Carton C consists of a hollow, open or tray-like cover section at havinga fiat top-forming panel b integrally bounded by tapered end and sidewalls c, d, respectively. Cover section c is integrally hinged by alongitudinally extending crease e to a cellular bottom section 1 of thecarton, these'sections being in generally coplanar relation' as removedfrom the apparatus after drying.

Cellular bottom section is subdivided by integral upstanding transverseand longitudinal partition elements g, h, respectively, into a pluralityof cells i, and upstanding post elements j, with which the partitionelements merge, assist in defining the cells. Finally, an internallydisposable reinforcing and locking flap k of the cartonis integrallyhinged to bottom section f by a longitudinally extending crease I, thisflap lying coplanar with the exposed margins of the cover and bottomsections.

The walls of cover section a and flap k are provided with undulatoryformations, generally designated m, to increase theegg accommodatingspace within the carton, and anesesntial feature of carton C is that itis provided with locking apertures n in its outer or free cover sectionwall d. One margin of each of these apertures practically coincides withthe meeting zone of the wall (I and top forming panel b.

The carton is characterized by a snap locking engagement in apertures 11of externally projecting locking lugs 0 formed adjacent the outer freeedge of the cover enclosed locking flap k, the lugs being caused to snapoutwardly into the apertures u when brought into horizontal registertherewith. Accordingly, it is the objective of the improve'ment shown inFigs. 4-8 to form apertures 11 in such a manner that they presentclean-cut and sharply defined margins, free from featheredge, declzleefiect or roughnes's, such as will of course substantially detract fromthe elfective'ness and positivenss of the desired snap locking action.

Turning, then, to Fig. 4, it will be noted that forming die as mountedin holder 48 is shaped in an outline corresponding to that of thearticle depicted in Fig. 3. Fig.4 shows only a single forming die 49 andindividual die holder 48 therefor, it being noted that a number of theseare assembled and bolted to the outer surface of a platen 47, insuccession longitudinally of the axis of the apparatus (Figs. 1, 2 and10). These dies are of composite, built-up character, in that eachthereof is composed of a single, full length, cover fannin die sectioii81,

again: when re rintin enter 5- arid wane a; a of the ear fif fife depsited; at stunt-nan lio'tffiffi forming seetioii 82 a'bi tfe'dag'a'iiist section 81 along a longitudinally extending joint 83',against which section the" bottom f and it's c'e ran-Insane g, It, i;j'aife molded; and a third nape? flange forming. section s4 abut'tedagainst sectien' s2 ale-fig a longitudinal joint as.

The cover and flap moldiiig' die sections 81, 84 are each fo rhid as asingle piece, bh't the intermediate c'ellrdnrtng' semen 82"is assemtqefrom a number of con p'oiriefit' shaped die elements. These include aplurality of individual, intermediate cell forming elements 86 6f whichthefeaieifiiie in the illustrated adaptation, and a pair of: efidfzi'sllforming sections 86 arran ed at the opp'esne ends of a longitudinalsuccession of the elerhei-itsl The foimiflg' elements 8 6, 86 of bottomformtrig" section 52 sre. abuttied against one another attransvei's'joirit' lifi s' s7, 'a"nd' theyare secured in this assemhlyby lofigi'th'dirially extefiding tie rods 88 passing tlifdughinfegi al'depending flanges on the respective component ceIl forming sections 86,86'. Similarly, the tines time; eese at to "g die 49', re, cover, bettoifi and flip forth 'seetidns 81, 82 and 84, respectively, are securedin their abutted engagement at joints 83', by'mahs of transverselyextending tie rods 91, these tie rods extendingthrough integraldepending webs ofth thfee' r'espeefive major sections. A built-up die ofthis hafac'te'r presents i terany' extending flanges 94 (Fig. 5)' at themargins of the component sections and is secured sppr snatiy at thoseflanges, as by bolts, s51; oithe like, to a corresponding adjacentflange 95" f vit's -ass5eiated die holder 48, in the fashion shown.gtancri. W

'Die' 49 i's'priivided'thre ug'hout its molding area with a'multiplicity of perforations 96 of, say, one sixteenth inch diameter,arranged on half inch centers, for the presen er admitting suction to awire mesh molding screen 97 which is shaped against and held in fixedrela tion to the contours" of the respective die sections 8 1, 32,134.

Themes don'sti tuted screen die is clamped at its margins g tby rneansof margin straps, as illustrated in Figs. land" 5' Theseiiicliide acover outer side margin strap' 9%,a 1' ir'is'frap' 99 adjacent eitherend of the die, and

I iii stfa'p 1'00: paralleling strap 98 at the opposiie,'fip' side' ofdie 49 and holder 48. Straps, 98, 99, 1043' are co'fi't'ou'fd alongtheir inner margins in approximate conformity with the external outlineof die 49; they are Seen-ed in clamping relation to the die screen 97'and die rriar'gins by means of screws or the like.

As mentioned above, and as shown in Figs. 2 and 10, each large platen 47has a set of the dies and die holde 'r's rigidly secured thereto in alongitudinally spaced, axially extending succession. The rear of theplaten is shown in Fig. 9. It is ofheavy gauge construction, andprovision is made to mount pressure distributor header 45 longitudinallyacross the rear surface thereof in flush relation thereto, as bygrooving the platen longitudinally to' receive" the header snugly.Platen 47 is provided with a number of relatively large sized openings191 through'whichvacuum chamber 23 of suction box 22 (Figs. l an'd 2.)is communicated with the interior of the die hold'ersefi'. Theseopenings of course have function only in the" ssetien molding andarticle transfer operations at the apparatus; they have no bearing onthe particular jetting" operationperformed by the present imprevement.

Referring specifically now to Figs. 48, each of the ester forming diesections 81 of the dies 49 assembled with a given platen 7 is providedwith a pair of side openings fill positioned in the" same relation tothe wall of this section as the covef lock apertures n of the cartenbear to the d of the latter, as depicted in Fig. 4. Adjfidiif marginsof'inesh screen 97 may be drawn outwardly intoathese openings :102 (Fig.5) and held in place by jet assembly 80. V t t t The construction of theindividual jet assemblies 80 is of importance in regard to the mosteflicient operation of the machine as a whole. Each such assemblycomprises an outer jet shell103 having a main'tubular body portion 104of rectangular cross sectional outline, i.e., corresponding to theoutline of the desired aperture n and the outline of die aperture 102.As appears in Fig.

8B, the forward extremity of shell body 104 is outwardly flanged at 105on its top and sides, thereby. enabling a secure grip to be exerted. onthe screen -97 adjoining aperture 102. Body 104 merges rearwardly into acylindrical tubular tail portion 106 which is internally threaded at 107and is snugly receivedin a circular aperture 108 of the wall of dieholder 48, with body 104 inclined downwardly and outwardly.

A jet core 109 (Fig. 8A) 'is frictionally received in the rectangularinterior of jet shell 104. This core has a solid forward body portion110 of rectangular outline corresponding in shape to that of the shellinterior, but of substantially less cross sectional area. Body 110flares forwardly and outwardly at. its top and sides in jet-directinglips 111, it being'noted by reference to Fig. 8B that the forward upperextremityof shell 104 is curled upwardly (also at its sides) at 112 insubstantial parallelism with the respective adjacent flared lips 111. In

obtaining a configuration of.the core body 110 as described, the same ismilled at its top and sides vto provide similar under-cut recesses 113which open forwardly to jet orifices of limited size, variable at willin accordance with the relative axial positioning of jet core 109 inshell 103. The bottom surface of jet core body 110 is left fiat, thebody being cut away only slightly at 113 to afford a further small,forwardly opening jet orifice between the core and shell in this,particular bottom area.

Core 109 is completed-by four rearwardly extending prong-like legs 114to hold the same frictionally in the shell, which legs are spaced fromonef another at the respective four corners of the body 110. Inrecessing of core body 110 at 113, 113 the core is placed incommunication at its top, bottom and sides with the space between thelegs 114, hence in free communication with the pressure supply end ofjet assembly 80.; Legs 114 serve a significant purpose in directing theair jet components in the proper directions and in the proper relativevolumes of flow to create a proper, though limited, fiber displacing jetaction at the top, sides and bottom of the carton aperture. j I

A hollow tubular clamp screw 115 is threaded into the rear 107 of jetshell 103, engaging die holder bore 108 to rigidly lock the jet assemblyin place, with a sealing gasket 116 interposed. An internal bore 117 ofthis clamp screw opens to the manifold passage 118 of a speciallyshaped, transversely extending manifold 119, such a manifoldbeingsecured to the side wall of each die holder 48 in covering relation tothe intake bores of the pair of jet assemblies 80 thereon. As indicatedin Figs. 1 and 2, each manifold 119 is upwardly connected through abore120 at each end thereof and through a grommet-sealed aperture 121 inplaten 47 with the main pressure distribution header 45, as illustratedin Figs. 1, 2, 4, 9 and 10. Hence air supplied through the swiveledpiping arrangement of Figs. 1 and 2 is distributed through header 45 andindividual manifolds 119 of the respective die holders 48 into the jetassemblies 80 thereof. This is done instantaneously and withoutsubstantial frictional resistance to flow.

An air stream entering the jet assembly from its rear is directedforwardly .and outwardly between the core legs or prongs 114 and intothe relieved marginal zones 113,113 of its body portion, being thencaused to travel in extremely restricted, outwardly divergent paths onthree sides of the bodyportion and in a restricted straight iQ W Id P thon the fourth or bottom side. A minute 10 high velocity currentflow-thus occursthrough indie vidually elongated orifices arranged atright angles to one another, and at just the proper position to sweepthe margins of the aperture formed at assembly as screen -97 emergesfrom the pulp slurry. Fibers in these zones are displaced sharply awayfrom the edges of the assembly with sufficient positiveness to outline acleancut pulp edge on all four sides of the assembly, yet ininsufficient volume and attendant impact to dislodge fibers immediatelyadjoining the edges. The undercutting and flaring of the cores top andsides at 113 is true and smooth as to radii and is such as to produce adeflection of the jets at these three surfaces, while the lesser bottomundercut at 113 produces a straight through flow.

The aperture n is thus ideally shaped for itsintended locking engagementwith lug 0.

Incidentally, reference has been made above to a jetting operationinvolving the use of air as the jetting medium; however the claimsemploy the term fluid in this connection, and it should be clearlyunderstood that the use of a liquid medium such as water in place of airis quite feasible and has been successfully practiced. Accordingly, theclaims should be construed in this light.

The reference numeral 125 in Fig. 2 conventionally designates the usualtank of the molding apparatus, containing a watery slurry of paper pulpfibers 126 the level of which is maintained approximately as indicatedat 127.

In the operation of the apparatus, the molding heads 11 are successivelyand continuously carried through the slurry 126, during which timesuction in vacuum chamber 23, created by means with which the presentinvention does not deal, is communicated through platen openings 101 onthe outer side of that chamber with the interior of a set of thebox-like die holders 48. Pulp fibers are drawn onto the surface ofmolding screens 97, but the area represented by the forward end of jetassembly 80 has no such deposition thereon, although there is a tendencyto build up the fibers around the margin of this area in a deckle orfeatheredge effect. However, as the screen emerges from the slurry airpressure is established by timing control valve 50.- As the successiveindividual pressure lines are exposed to the arcuate distributor groove51 of this valve in the rotation of distributor disk 14, the pressure istransmitted through the individual piping, including rotatable joint 40,to elongated distributor-header 45, whence individual manifolds 119transmit pressure to the jet assemblies 80 connected with each die 49.Built up wet fibers are dislodged by fluid shearing type of action fromthe zone of the aperture margin without appreciable disruptive effect.

Jetting action persists for a period of time determined by the angularextent of the low 78 on master valve control cam 76,. or by the angularextent of the internal groove of distributor valve 50, or both,whereupon pressure is shut off. The apparatus then transports themolding head 11 upwardly in an arcuate path to a conveyor for dryingforms (not shown), during which travel the individual molding headspartake of swiveling action about their respective rotating supports, ina manner and for a purpose not germane to the present invention. Uponarrival at the drying forms they are transferred thereto; and a similarmolding, jetting and transfer cycle ensues upon re-arrival of themolding head at tank 125.

I claim: I

1. Apparatus for forming apertured articles of molded pulp, comprising aforming die surface against which wet fibers are deposited in forming anarticle, said surface having an opening of the general outline of anaperture desired in the article, ajet unit having an imperforate corepresenting a surface exposed in said opening against which fibers do notdeposit, an orifice surrounding said last namedsurface with small sideclearance to afford a restricted jet orifice between the same and amargin of said first named opening, and means to 11 seabirds a fi uid'pressure line in communication with" said jet orifice. s

i. Apparatus for forming apertured articles of molded pulp, comprising aforming die surface against which we: fibers are deposited in forming anarticle, said surface having an opening of the general outline of anaperture desired in the article, and a jet unit disposed in saidopening, said unit comprising an internal core having" an imperforate'forward surface positioned within said opening against which fibers donot deposit, and a tubular shell surrounding said core surface withsmall side clearance to afford a forward jet orifice between the coreand shell.

3'. Apparatus for forming apertured articles of molded pulp, comprisinga forming die surface against which wet fibers are deposited in formingan article, said sur-' face having an opening of the general outline ofan aperture desired in the article, and a jet unit disposed in saidopening, said unit comprising an internal core having an imperforateforward surface positioned within said opening against which fibers donot deposit, and a tubular-shell surrounding said core surface withsmall side clearanceto afford a forward jet orifice between the core andshell, adjacent surfaces of said core and shell being flared forwardlyand outwardly at said jet orifice 4. Apparatus for forming aperturedarticles of molded pulp", comprising a forming die" surface againstwhich wet fibers are deposited in forming an article, said sun facehaving an opening of the general outline of an aperture desired in thearticle; and a jet unit disposed in said opening, said unit comprisingan internal core having an imperforat'e forward surface positionedwithin said opening against which fibers do not deposit, and a tubularshell surrounding said core surface with small side clearance to afforda forward jet orifice between the core and shell, said time having aplurality of elements extending rearwardly away from said imperforatesurface in releasable frictional engagement with the interior of saidshell. I

5. Apparatus for forming apertured articles of molded pulp, comprising aforming die surface against WhlCh' wet fibers are deposited in formingan article, said surface having an opening of the general outline of anaperture desired in the article, and a jet unit disposed in saidopening, said unit comprising an internal core having an imperforateforward surface positioned within said opening. against which fibers donot deposit, a tubular shell surrounding said core surface with smallside clearance to afford a forward jet orifice between the coreandshell, and means to establish a fluid pressure line through said jetunit to said jet orifice, said core having a plurality of elementsextending rearwardly away from said imperf orate surface in releasablefrictional engagement with the interior of said shell, said core beinglaterally recessed forwardly of said elements so as to connect saidorifice between said elements with said last named fluid pressure means.V s

6. Apparatus for formingapertured articles of rnolded pulp, comprising aforming die surface against. which wet fibers are deposited in formingan article, said surface having an opening of the general outline of anaperture desired in the article, and a jet unit disposed in saidopening, said unit comprising an internal core having an imperforateforward surface positioned within said opening against which fibers donot deposit, and a tubular shell surrounding said coresurface with smallside clearance to ali'ord a forward jet orifice between the core andshell, said core'having a plurality of of elements extending rearwardlyaway from said im'perforate surface" in releasable frictional engagementwith the interior of said shell, adjacent surfaces of said core andshell being flared forwardly and outwardly at said jet orifice.

Apparatus for f orrningapert'ured articles of molded purp; comprising aforming die surface against which wet o 12 filb'ers are de osited informing an article, said surface having an opening of the generaloutline" of an aperture desired in the article, and a" jet unit disposedin said opening, said unit comprising an internal core having animperfora'te forward surface: positioned within said opening againstwhich fibers do not deposit, a tubular shell surrounding saidcoresurface with small side clearance to afiord' a forward jet orificebetween the core and shell, and to' establish a fluid pressure linethrough said jet unit to said jet orifice, said core having a pluralityof elements' extending rearwardly away from said imperforate surface inreleasable frictional engagement with the interior or said shell, saidcore being laterally recessed forwa'rdly of said elements so as toconnect said orifice between said elements with said last named fluidpressure means, adjacent surfaces of said core and shell being flaredforwardly and outwardly at said jet orifice.

8. Apparatus for forming apertured articles of molded pulp, comprising aforarninate molding form, means for molding a wet article on said form,including a movable support on which said form is mounted to transportthe same through aslurry of fibers and means to deposit under suction alayer of said fibers on a surface of said form asit traverses saidslurry, said surface having an imperrorate area which is bounded atleast in part by a restricted jet orifice, and a pressure supply line todischarge fluid through said jetorifice and thereby create at saidorifice a jet for defining a margin of an aperture in said articleresulting from the non-deposition of fibers at said impeffo rate area.

9'. Apparatus for forming apertured articles of molded pulp, comprisinga foraniinate molding form, means for rnolding a wet article on saidform, including a movable support on which-said form is mounted totransport the same through a} slurry of fibers and means to depositunder suction a layer of said fibers on a surface of said form as ittraverses said slurry, said surface having an imperforate area which isbounded at least in part by a restricted jet orifice, a pressure supplyline to discharge fluid through said jet orifice and thereby create atsaid orifice a jet for defining a margin of an aperture in said articleresulting fromthe non-deposition of fibers at said imperforate area, andmeans'operating in timed relation to movement of said form support toforward fluid through said line upon emergence of said form surface fromsaid slurry.

10. Apparatus for forming apertured articles of molded pulp, comprisinga foraminate molding form, means for molding a wet article on said form,including a movable support on which said form is mounted to transportthe same through a slurry of fibers, means pivoting said form on saidsupport, and means to deposit under suction a layer of said fibers on asurface of said form as it traverses said slurry, saidsurface having animperforate area which is bounded at least in part by a restricted jetorifice, and a pressure supply line to discharge fluid through said jetorifice and thereby create at said orifice a jet for defining a marginof an aperture in said article resulting from the non-deposition offibers at said imperforate area, said supply line including fixed pipingand a joint rotatable about its axis for placing the same in pressurecommunication with said orifice.

11. Apparatus for forming apertured articles of molded pulp,; comprisinga foraminate molding term, means for molding a wet article on said form,including a movable support on which said form is mounted to transportthe same through a slurr of fibers, means pivoting said form on saidsupport, and means to deposit under suction a layer of said fibers on asurface of said form as it traverses said slurry, said surface having animperforate area which is manned atfleast in part by a restricted jetorifice, a pre sure supply line to discharge fluid through said jetorifice and thereby create' at said orifice a jet for defining arnargifi'or a erture insaid article resulting" from the non-depositionor fibers at said imperforate area, said supply line including fixedpiping and a joint revolving about its own axis for placing the same inpressure communication with said orifice, and means operating in timedrelation to movement of said form support to forward fluid through saidline upon emergence of said form surface from said slurry.

12. A foraminous mold for forming molded pulp cartons having coversections which interlock by the engagement of apertures and projectinglugs formed therein, comprising a plurality of associated die sectionscontoured to form such a carton including its cover sections, a wiremesh screen covering each of the die sections for the deposition of pulpfibers thereon to form a carton, one of said die sections havingprojections designed to form the projecting lugs and another one of thedie sections having openings corresponding to the apertures desired in acarton molded thereon, a jet unit mounted in each of said openings, eachjet unit having an imperforate core projecting through the screen andpresenting a surface against which fibers do not deposit, and an orificeclosely surrounding each core and communicating with a source of fluidpressure.

13. Apparatus for forming apertured articles of molded pulp, comprisinga forming die surface against which wet fibers are deposited in formingan article, said surface having an opening of the general outline of anaperture desired in the article, and a jet unit disposed in saidopening, said unit comprising an internal core having an imand a tubularshell surrounding said core surface with a 14 small side clearance toafford a forward jet orifice between the core and shell.

14. The method of forming a molded pulp article having an aperturetherethrough comprising immersing a suction mold in a slurry of pulpfibers and applying suction thereto to draw liquid inwardly of the moldand form a layer of interlaced pulp fibers on the surface of the mold,then withdrawing the mold from the slurry, and'then directing a hollowstream of gas under pressure from the interior of the mold outwardly ofthe mold through the layer of pulp on the mold so that thin marginalportions of said stream are directed along the outline of the desiredaperture while maintaining suction within the mold to hold the layer offibers in position on the mold and while the fibers are wet andrelatively free to slip apart from each other.

References Cited in the file of this patent UNITED STATES PATENTS

13. APPARATUS FOR FORMING APERTURED ARTICLES OF MOLDED PULP, COMPRISINGA FORMING DIE SURFACE AGAINST WHICH WET FIBERS ARE DEPOSITED IN FORMINGAN ARTICLE, SAID SURFACE HAVING AN OPENING OF THE GENERAL OUTLINE OF ANAPERTURE DESIRED IN THE ARTICLE, AND A JET UNIT DISPOSED IN SAIDOPENING, SAID UNIT COMPRISING AN INTERNAL CORE HAVING AN IMPERFORATEFORWARD SURFACE POSITIONED WITHIN SAID OPENING AND A TUBULAR SHELLSURROUNDING SAID CORE SURFACE WITH SMALL SIDE CLEARANCE TO AFFORD AFORWARD JET ORIFICE BETWEEN THE CORE AND SHELL.
 14. THE METHOD OFFORMING A MOLDED PULP ARTICLE HAVING AN APERTURE THERETHROUGH COMPRISINGIMMERSING A SUCTION MOLD IN A SLURRY OF PULP FIBERS, AND APPLYINGSUCTION THERETO TO DRAW LIQUID INWARDLY OF THE MOLD AND FORM A LAYER OFINTERLACED PULP FIBERS ON THE SURFACE OF THE MOLD, THEN WITHDRAWING THEMOLD FROM THE SLURRY, AND THEN DIRECTING A HOLLOW STREAM OF GAS UNDERPRESSURE FROM THE INTERIOR OF THE MOLD OUTWARDLY OF THE MOLD THROUGH THELAYER OF PULP ON THE MOLD SO THAT THIN MARGINNAL PORTIONS OF SAID STREAMARE DIRECTED ALONG THE OUTLINE OF THE DESIRED APERTURE WHILE MAINTAININGSUCTION WITHIN THE MOLD TO HOLD THE LAYER OF FIBERS IN POSITION ON THEMOLD AND WHILE THE FIBERS ARE WET AND RELATIVELY FREE TO SLIP APART FROMEACH OTHER.